Re: [Boost-users] [lambda] newbie: lambda to help in std::accumulate

2009/1/25 Michał Nowotka :

I want to compute sum of logarithms so i wrote:

#include <cmath>

double evaluate(const vector<double>& win_probabls) { return accumulate (win_probabls.begin(), win_probabls.end(), 0, lambda::_1 + log(lambda::_2) ); }

but this code doesn't compile. Does anyone know why?

--

Michał Nowotka

'log' is a function, so a call to it in a lambda expression has to be within a bind expression: double evaluate(const std::vector<double>& win_probabls) { using namespace boost::lambda; return accumulate (win_probabls.begin(), win_probabls.end(), 0, _1 + bind(log, _2) ); } Stuart Dootson